A quantum scandal surrounding Microsoft: physicist debunks the myth of the topological qubit
Microsoft's bold claims about creating a topological qubit, which were supposed to mark a breakthrough in quantum computing, have faced a serious challenge. Physicist Henry Legg from the University of St Andrews published a critical analysis in Nature of Microsoft Azure Quantum's key paper from February 2025, questioning the interpretation of the experimental data.
Dubious Signals and the Absence of a Gap
Legg analyzed the transport characteristics of the device described in Microsoft's work. His main argument: the data does not demonstrate a stable superconducting gap in the areas where the company claimed to read parity. Without this gap, as the physicist explains, the interpretation of the measurements as topological loses its justification. The signals that Microsoft presents as evidence of a topological regime, according to Legg, could be explained by much more prosaic effects — for example, quantum dots or disorder within the device itself.
Microsoft's Response: "We Stand by Our Results"
The corporation did not stay silent. On the same day, Nature published an official response from Microsoft, where the authors categorically reject the criticism. They claim that their measurements do not require an a priori assumption of the existence of a superconducting gap, and the observed signals are fully consistent with a topological state. Microsoft Quantum Hardware Technical Director Chetan Nayak emphasized: "We stand by our results and our roadmap." As indirect confirmation, he cited Microsoft's participation in the DARPA US2QC program, where the agency selected the company for the verification and co-design phase of a quantum computer by 2033.
Connection to Majorana 2 and the Roadmap
This dispute extends far beyond a single paper. In June 2026, Microsoft introduced a new topological chip, Majorana 2, claiming an average qubit lifetime of 20 seconds (up to a minute in some cases) and operation speeds of about 1 μs. The company attributed the progress to replacing aluminum with lead and using Microsoft Discovery AI tools. However, Legg's commentary does not directly address Majorana 2, but rather the 2025 paper on InAs–Al devices that underlies Majorana 1. This means the very technological platform on which Microsoft's new roadmap is built is being called into question. Physicist Sergey Frolov from the University of Pittsburgh has already stated that Microsoft's work in Nature likely should be retracted.
My Expert Opinion: This incident is a classic example of how ambitious claims in quantum physics crash against the harsh reality of experimental verification. For the crypto industry, which places great hopes on quantum resilience, this is a worrying signal: topological qubit technology is still far from maturity, and roadmaps based on disputed data are not trustworthy. While Microsoft deals with the criticism, D-Wave has already unveiled its plan to create 100 logical qubits by 2032 — and that looks far more realistic.